Dongfeng Motor Corp. said on Friday it removed Ren Yong, assistant to the general manager, from his duties at the state-run company and at its joint venture with Nissan.

In a separate statement, the Central Commission for Discipline Inspection, the Chinese Communist Party’s top anticorruption body, said Mr. Ren was under investigation for suspected serious violations of party discipline and law, without elaborating.

A Dongfeng representative said she didn’t have any further comment. A spokesman at its joint venture with Nissan, Dongfeng Nissan Passenger Vehicle Co., said the company’s business and daily operations haven’t been affected and remain as usual. He didn’t provide further information on the probe.

Mr. Ren didn’t return phone calls and emails seeking comment. The executive had held the position of vice-general manager at Dongfeng Nissan.

Several executives of large state-owned companies have been put under investigation amid Beijing’s prolonged anticorruption drive. That includes the auto industry, where previously current and former Chinese executives at a Volkswagen AG joint venture with state-owned FAW Group Corp. were put under investigation. Volkswagen hasn’t been accused of wrongdoing on that matter.

Dongfeng’s Hong Kong-listed unit
Dongfeng Motor Group Co.
said Mr. Ren had been temporarily suspended from his administrative duties at that company, where he serves as a supervisor. The listed company said in a statement to the stock exchange it had resolved to remove him from the position, pending shareholder approval. It didn’t provide further details.

Dongfeng is one of China’s largest car makers. But the overwhelming majority of Dongfeng’s cars are produced with the company’s foreign joint-venture partners, which include Japanese auto makers Nissan and
Honda Motor Co.
, as well as French auto maker PSA Peugeot Citroën. Under Chinese law, foreign auto makers must partner with local companies to assemble cars in China.

Dongfeng is among a number of Chinese car makers with a focus on going abroad. In February, Dongfeng Motor invested $1.1 billion in the struggling PSA Peugeot Citroën, becoming one of its leading shareholders.

Nissan is the largest Japanese player in China by sales. Dongfeng Nissan sold more than 850,000 vehicles in the first 11 months of the year, up 3.9%—considerably lower than the 9.2% recorded in the broad passenger car market during the same period.

Auto-sales growth in China, the world’s largest car market, has slowed amid a slackening economic expansion and rising competition. In October, Nissan cut its sales projections for China this year. It now aims to sell 1.27 million vehicles this year, compared with 1.4 million vehicles it had targeted earlier.

Yale Zhang, managing director of consultancy Automotive Foresight, said Nissan’s momentum in China is slowing as it meets with intensified competition from U.S. and European brands in China, including from PSA. He expected the situation to further deteriorate in 2015 as competitors add significant amounts of new capacity to a market where sales growth is already slowing.

A spokesman for Dongfeng Nissan said sales have been growing in China amid a market where competition is “fierce.”

“Nissan is and will remain committed to the Chinese market,” he said, adding that the company will offer three new passenger car models in 2015 and a sport-utility vehicle under its for China brand Venucia. “With these, we believe that we will grow sales,” he said.